There is increasing demand for technology to maintain the mobility of an aging worldwide population. Joint replacement is widely recognized as a successful orthopaedic surgical procedure for treating degenerative musculoskeletal conditions. However, joint replacement prostheses have limited longevity, especially in younger and more active people. Efforts to improve prosthesis longevity and performance continue to drive changes in surgical techniques, prosthesis materials and designs. The broad objective of this proposal is to improve the longevity of joint replacements by expanding our understanding of the biomechanical environment in which prostheses function and wear. The approach is to assess the performance of explanted prostheses after they have endured a finite duration of function in a human physiological environment. Such assessments provide essential inputs for prosthesis development and for validating preclinical methodologies for predicting joint prosthesis performance. However, access to explanted prostheses is limited and few European research groups are participating in such assessments. This proposal (ORTHOWATCH) aims to strengthen the procedures and outcomes of a recently established Register of Orthopaedic Prosthetic Explants (REPO) at the Istituti Ortopedici Rizzoli, a leading European institute for orthopaedics and traumatology. ORTHOWATCH will integrate outcome registers, retrieval analysis programs and preclinical validation methods into a synergistic post-marketing surveillance program for orthopedic devices. The objectives of ORTHOWATCH are: 1) to implement a standardized screening protocol for categorizing explanted prostheses; 2) to apply existing measurement technologies for quantitative assessment of explanted prostheses; and 3) to provide quantitative endpoints from the explanted prostheses that are complementary to the research objectives of a multidisciplinary team of researchers within the host organization.